Dietary Changes of Youth during the COVID-19 Pandemic: A Systematic Review

Background The coronavirus disease 2019 (COVID-19) pandemic has taken the lives of millions and disrupted countless more worldwide. Simply living through the pandemic has had drastic effects on the health of citizens. Diet, an important aspect of health, has been uniquely affected by the pandemic, although these changes have not been sufficiently studied among youth. Objectives The objective of this systematic review was to investigate dietary changes of youth during COVID-19. Methods A prespecified literature review was conducted using MEDLINE, EMBASE, Scopus, and CINAHL to identify studies from January 2020 to May 2023 that assessed dietary changes among youth aged ≤20 y compared with before the pandemic. Only quantitative observational studies that were published in English were included. Two authors completed all screening/study selection independently, with disagreements being resolved via discussion. Data extraction was completed by 1 author. Dietary changes were categorized into food groups and habits for analysis purposes. Results In total, 67 studies met inclusion criteria. Most studies used recall to assess changes (48/67; 71.6%). Most studies found an increase in fruits and vegetables (24/46; 52.2%), grain products (6/11; 54.5%), meat, poultry, and eggs (4/8, 50.0%), diet quality indices and/or overall dietary assessments (7/13, 53.8%), and the frequency of snacking (9/12; 75.0%), whereas generally finding a decrease in ultraprocessed foods (32/53; 60.4%), compared with before the COVID-19 pandemic. Mixed findings or primarily no changes were found for fish and aquatic products, legumes, beans, seeds and nuts, milk and milk products, breakfast consumption, and nutrient intake. Conclusions Mostly favorable dietary changes appear to have occurred among youth during COVID-19, although there were several mixed findings and unclear takeaways among the foods and habits under study. The heterogeneity of defining food groups was a noted limitation in the current review.


Introduction
The COVID-19 is responsible for ~6.9 million deaths since the WHO first declared it a pandemic on March 11, 2020 [1].Because of the severity and infectious nature of this disease, more than one-third of countries worldwide began implementing restrictive measures for citizens in March 2020, in hopes to slow the spread [2].In the months following, many countries began adopting policies, such as mandatory masking indoors, capacity limits of buildings, shifting work and school to online formats, and temporary closure of nonessential businesses, such as restaurants, bars, and recreational facilities [3][4][5][6].Although these restrictions have been effective at reducing the spread of the COVID-19 virus, there have been unintended effects of the Abbreviations: HDI, Human Development Index; KIDMED, Mediterranean Diet Adherence.☆ This systematic review was registered at PROSPERO as CRD42023412766.
pandemic on both the mental and physical health of individuals of all ages.
In a systematic review on the impact of the COVID-19 pandemic on the mental health of adolescents worldwide, living through the pandemic was found to be associated with higher anxiety, depression, and psychological distress, compared with prior [7].A separate systematic review found that the pandemic has also been associated with reduced physical activity in youth, compared with prior [8].Beyond these effects, the COVID-19 pandemic has brought on other negative changes for families as well, including loss of employment [9], reduced food security [10,11], and increased substance use, particularly alcohol [12].
Although these changes are important to investigate, dietary changes during the COVID-19 pandemic are especially important to consider, given the association that dietary intake has with risk of future chronic disease [13].Potential reasons for dietary changes during the COVID-19 pandemic are numerous and include interruptions to the global food supply chain [14], increased boredom because of temporary stay-at-home measures [15], reduced food security [11], and increased sedentariness/screen time [16].It is likely that these changes have collectively influenced a shift in dietary changes of people worldwide affected by the pandemic, coupled with the stress and anxiety that come with living through unprecedented times.
Most research investigating the impact of the COVID-19 pandemic on dietary intake has focused mostly on an adult population, with 2 previous reviews finding mostly unfavorable changes, including an increased consumption of alcohol, snacking, and ultraprocessed foods compared with before the COVID-19 pandemic [17,18].It is important to note however, that youth are also susceptible to the effects of the pandemic [19].Childhood and adolescence are critical periods of growth, as adults who developed food skills during their childhood and teen years have been shown to have more confidence regarding their cooking and food skills, cooking practices, attitudes, and diet quality, compared with those who did not develop these skills at these ages [20,21].If the COVID-19 pandemic has negatively affected dietary habits among youth, these unhealthy habits and reliance on foods that require little cooking/preparation skills (e.g., ultraprocessed foods) may continue postpandemic and carry forward into adulthood, putting them at risk of chronic diseases, such as cardiovascular disease, obesity, various cancers, type 2 diabetes, and depression [22][23][24].
In a recent systematic review, authors investigated eating habits of children and adolescents during lockdowns globally, finding mixed results, such as increases in consumption of homecooked meals, fruits, vegetables, and legumes, but also increases in foods, such as french fries and sweets [25].Although this paper contributes to the knowledge of how youth's diets have changed during COVID-19, it is limited in that it only considers dietary changes during "lockdowns," which are heterogeneous in nature and vary in definition, by region.The COVID-19 pandemic has had drastic effects on a global scale, and although lockdowns have certainly contributed to these changes, the impacts which the COVID-19 pandemic has had extend beyond these lockdowns.Given the risk of chronic disease that has been routinely associated with poor diet quality [26], and the critical time-period which youth have to develop their food skills [20,21], it is vital that this population be investigated to see how the entirety of the COVID-19 pandemic has impacted their diets.As such, the purpose of this systematic review was to examine the dietary changes of youth ( 20 y) during the COVID-19 pandemic, compared with before the pandemic.

Methods
The protocol for this systematic review is registered on PROSPERO (#412766) and was conducted in accordance with the PRISMA statement [27].

Information sources
Searches were conducted by one author (NW) using MEDLINE (Ovid), EMBASE (Ovid), CINAHL, and Scopus.The search was conducted in May 2023, using a combination of keywords and section headers, after consultation with an academic librarian who helped refine the search.Papers were limited to those published from January 2020 to May 2023.The search strategy for each database can be found in Supplemental Table 1.

Inclusion/exclusion criteria
Quantitative observational studies were included if they investigated dietary changes during the COVID-19 pandemic (compared with before the pandemic) among youth aged 20 y and were published in English.The timing of both "before the pandemic" and "during the pandemic" was left up to authors' discretions; however, all dates of data collection ranged from March 2018 to April 2022.Dietary changes included shifts in food and/or nutrient intake, frequency of meals/snacks, diet quality scores, frequency of takeout food consumption, and intake of certain foods/food groups (e.g., fruits and vegetables, milk products).For younger ages, parents' perceptions of their child's food changes were recorded, although studies, which investigated total household changes and gave no description about youth changes were excluded.Studies were also excluded if they investigated dietary intake during the COVID-19 pandemic but did not inquire about dietary intake before the COVID-19 pandemic.Studies were included if the sample included age ranges beyond the one under study (i.e., >20 y), permitting that data for youth were stratified for, or in cases where data were not stratified, if the mean/median age was 20 y.Studies were excluded if the sample was limited to youth with a specific disease (e.g., inflammatory bowel disease), or those involving inpatient settings and/or other health services recruitment.Intervention studies were also excluded for the purposes of this review, as only dietary changes because of COVID-19 were investigated.Qualitative studies were also excluded if no quantitative component was included.

Study selection
Results of the searches were exported via a research information systems file and imported into COVIDENCE Systematic Review Software for screening [28].Two reviewers (NW and HS) completed the title and abstract screening based on the inclusion and exclusion criteria.Reviewers first completed this step independently and then resolved disagreements via discussion using COVIDENCE [28], which flagged conflicting responses.Duplicates were excluded before screening.Next, full-text screening was completed independently by both reviewers, for all articles that were selected for inclusion from the previous stage.
Disagreement was again resolved using discussion.Articles were selected for inclusion, or excluded with reasons, which can be found within the PRISMA diagram (Figure 1).

Data extraction
Data extraction was completed by 1 author (NW) using a custom created extraction chart that included: authors, number of participants, sample size, age range (or mean age AE SD, when the range was not given), gender/sex distribution, the method used to measure dietary changes, the dietary measures investigated (e.g., food groups, diet quality scores), the country the data were derived from, dates of data collection, method of reporting (parent compared with self-reported), method of comparison (prepandemic measurement compared with participant recall), and key findings of the articles.The Human Development Index (HDI), designed by the United Nations to represent a nation's level of development on a scale of 0-1, was determined based on the countries studied, and a value was applied to each country based on the 2021 report (the most recent at time of writing) [29].Any information not provided within the articles was treated as missing.

Food group measures
Individual foods were categorized into food groups to analyze changes from a macro-level standpoint and to clarify and synthesize results.The following food groups were used: "Fruits and Vegetables," "Fish and Aquatic Products," "Grain Products," "Legumes, Beans, Seeds, and Nuts," "Meat, Poultry, and Eggs," "Milk and Milk Products," and "Ultra-Processed Foods."These food groups were created by 1 registered dietitian (NW) to summarize findings and were based on pre-existing, commonly used food groups, such as those used in "Eating Well with Canada's Food Guide" [30] and the "Mediterranean Diet Quality Index Questionnaire" [31].Combinations of 2 or more food groups, or measures of food intake changes that did not apply to any of the above food groups, were not classified."Diet Quality Indices and Overall Assessments," "Nutrients," "Breakfast," and "Snacking" were also assessed (despite not fitting in the above food groups), because of the number of studies investigating these habits.The grouping of these categories can be found in Supplemental Table 2.

Data synthesizing
Each food or dietary habit within a study was assigned to its overarching group (e.g.Fruits and Vegetables and Snacking).If the study found an increase in at least one of these foods within that category, the study was classified as finding an increase, and the same applies if a decrease was found.If none of the foods within a group changed, the study was treated as finding no difference.If the study found both an increase and decrease of foods/ habits from a specific group, the study was treated as finding both an increase and decrease for that group.Finally, studies which found changes (either an increase or decrease), but did not present statistical significance, were still treated as changes, whereas those that did present statistical significance were treated as changes only if significance was met.However, each change (or lack thereof) was noted as either a statistically significant one or not, to avoid biasing findings based on descriptive studies.

Quality assessment
Studies were graded on their quality using the National Heart, Lung, and Blood Institute's Quality Assessment Tool for Observational Cohort, and Cross-Sectional Studies (National Heart, Lung, and Blood Institute, 2021), based on 14 different scoring metrics.Inherent to the current review's objectives, 4 of these scoring metrics were not relevant as they pertained to varying levels of the exposure, measurement of exposure, and the blinding of the exposure measurement.As the current study's exposure variable is living through the COVID-19 pandemic, these were not included, and only 10 scoring metrics were used to assess quality.Studies were given a total score out of 10 (1 for each category), dependent on how many criteria each met.Two authors (NW and HS) completed the quality assessment independently for all studies, with disagreements resolved via discussion.To ensure consistency with overall findings, each domain of dietary changes was assessed, stratified by study quality (see Supplemental Table 3).For the purposes of this subanalysis, studies with a score of 6 or higher were deemed "high quality," scores of 4-5 were deemed "medium quality," and those with a score of 3 or lower were deemed "low quality."Dietary changes among each level of study quality were compared on the number of studies suggesting an increase, decrease, or no change.

Results
A total of 4702 articles were originally retrieved for screening.On completion of title, abstract, and full-text screening, 67 studies were deemed eligible for inclusion (Figure 1).The median number of youth participants across studies was 782.5 (range: 50-109, 282), and ages of youth ranged from 1 to 20 y.Dates under study ranged from March 2018 (prepandemic reference) to April 2022 (during pandemic), although most studies collected data during January-December 2020.More information on characteristics of the studies can be found in Table 1 , and a summary of the quality assessment can be found in Table 2.

Method of food intake assessment
Most studies used either a food frequency questionnaire or alternative questionnaire to inquire about dietary changes (62/ 67; 92.5%).A 3-d weighed diet record was used by 1 study, whereas a 24-h dietary recall was used by 4 studies.Prepandemic measurements of dietary intake were used as comparison tools in 20 studies, and among these studies, 14 used the same cohort of youth for both measurements, whereas 7 used a separate group of youth for the 2 timepoints (1 study used both).Most studies (n ¼ 47) relied on participant recall comparing dietary intake before and during COVID-19.

Country of study/HDI
A total of 31 different countries were included in this review.Spain (n ¼ 7), Poland (n ¼ 6), and the United States (n ¼ 6) were the 3 most studied countries, whereas most studies came from within Europe (n ¼ 31).Other countries included Australia, Korea, Saudi Arabia, Italy (n ¼ 5 for each), China, India (n ¼ 4 for both), Brazil, Germany, Greece, United Kingdom, Canada, Chile, Japan, Jordan, Turkey (n ¼ 2 for each), Croatia, France, Czech Republic, Egypt, Cyprus, Palestine, Colombia, Ethiopia, Burkina Faso, Lebanon, Netherlands, Slovakia, and Nigeria (n ¼ 1 for each).HDI values ranged from 0.45 (Burkina Faso) to 0.95 (Australia), although most countries where studies took place are classified by as "High" to "Very High" development (n ¼ 63/67, 94.0%), based on their scores.

Study quality
The median study quality score was 4 (out of 10), which was also the most common score.The study quality scores ranged from 1 to 9, although only 1 study received a 9/10 score.The most common reasons studies had lower scores were because they failed to disclose or did not have a participation rate of eligible people >50%, not providing a sample size justification, having a cross-sectional study design, and not controlling for important covariates in the analysis.Finally, subanalysis of each domain by study quality revealed largely that although results did not drastically change, higher quality studies were more likely to produce null findings (see Supplemental Table 3).Overall, study quality results are presented in Table 2.

Changes in Food Consumption/Habits
Overall study findings are summarized below (Figure 2).
Finally, 1 study found a significant change in fish consumption, but it cannot be determined in what direction.

Discussion
This review examined youth's dietary changes during the COVID-19 pandemic, finding largely positive changes, beginning first with fruit and vegetable consumption.Most studies found an increase in fruits and vegetables, which is a positive change, as past research has shown that teens and younger children tend to not consume as many fruits and vegetables as recommended [99][100][101].These results are somewhat conflicting with a similar review which found that most studies found a decrease in fruit and/or vegetable intake among individuals of all ages during COVID-19 restrictions, compared with prior [18].One potential reason for this inconsistency is the differing populations investigated, as the prior review did not specifically study youth and included a mostly adult population.Second, even though this previous review found that most studies reported a decrease in fruit and vegetable consumption, the number of studies indicating a decrease was only slightly higher than the number suggesting an increase.(4-2, respectively) [18].Finally, these findings are in agreement with another previous review on the cardiometabolic risk factors of youth during COVID-19 by Karatzi et al. [102], who found a general increase in fruit consumption compared with before COVID-19.
Possible explanations for the increase in fruit and vegetable consumption in the current review are numerous, with one being the increased time parents may have had to spend at home with their children positively influencing this.In a previous systematic review investigating change in home cooking/culinary practices, one noted side-effect of COVID-19 restrictions (among those making positive changes) was the increased time some parents were afforded to cook home meals [103].In general, this may have caused an increase in fruit and vegetable consumption, because these foods often require time for preparation, which has been noted as a barrier to increasing produce consumption [104].Another potential reason could be related to the method of recall, as a minority of studies in this review used a longitudinal design method.As a result, for the other studies, relying on recall is necessary to document changes, but is susceptible to recall bias [105] and social desirability bias [106].Therefore, it is difficult to disentangle the impact which this may have had on the perceived increase of fruit and vegetable intake as youth (and their parents) may not be accurate in their recollections of intake.
Ultraprocessed foods were assessed by most studies in this review, and most found a decrease in consumption of 1 or more of these foods, compared with those which found an increase.Although again, increased parental oversight is a possible reason for the decrease, it should also be considered that during COVID-19 restrictions, some fast-food restaurants were severely restricted in how they were able to operate, which varied depending on governmental policies put in place [5].As such, although this can be seen as a positive change, it may not necessarily have been a conscious decision on the part of youth and could partially be regarded as a direct consequence of COVID-19 restrictions.In this sense, it is unclear whether this decrease in consumption will continue as restrictions have largely been removed.
It should also be noted that these findings are in direct contrast with a previous systematic review on the topic which suggested that there was an overwhelming increase in unhealthy ("junk") food during lockdowns among children and youth, compared with prior [25].One reason for this discrepancy may be the differences in coding of food groups, as well as the current review containing additional studies that investigated ultraprocessed foods (when compared with both previous reviews).For example, Pourghazi et al. [25] incorporated "snacks" as inherently "junk foods," which our review only did if the snack was clearly described as an ultraprocessed food.Another key difference is that our review classified almost 100 different foods as ultraprocessed foods (see Supplemental Table 1), whereas the previous review by Pourghazi et al. [25] listed 6 different food groups (snacks, fast foods, French fries or chips, processed food, and sweets) as "junk foods", making direct comparisons between the categorization of the reviews more challenging, because it is unclear how these food groups are further broken down.As such, the differences in these groupings and slight differences in inclusion criteria may have contributed to the contrasting findings between the 2 reviews.
Next, although most studies which investigated intakes of legumes, beans, seeds, and nuts found that youth tended to decrease their intake during COVID-19, results were largely mixed, as a similar proportion found an increase, or no change at all.These foods tend to offer a host of nutrients including fiber and plant-based sources of protein and have been recommended as important foods by the WHO to improve health and diet quality [107].Potential reasons for the discrepant findings are multifactorial, although 1 potential reason could be related to supply chain issues which many countries experienced during the COVID-19 pandemic [14].
Other changes included most studies finding an increase in milk and milk products, snacking, and grain products.It is difficult to ascertain whether these increases are favorable, as, for example, milk and milk products include a host of products which could be regarded as "healthy" (e.g., yogurt and low-fat milk), whereas others might be regarded as foods to be limited (e.g., cheese and sugar-sweetened milk) [108].Similarly, although grain products seem to have increased or remained stable during COVID-19, it is difficult to ascertain whether this is a positive change or not.Although most grain products (e.g., bread and pasta) provide important nutrients, there is a marked difference between refined grains and whole grains in terms of nutrient density, and by extension, health benefits [109], which most studies in this review did not differentiate between.Finally, although snacking increased, it is not inherently healthy or unhealthy [110], and is at least partially dependent upon the foods being consumed at these "snack" times, which was often not mentioned.Therefore, interpretation of the healthiness of these changes would be somewhat speculative.
This current review also found a similar number of studies suggesting either a decrease or no change in fish consumption during COVID-19, and a slight majority found an increase in meat, poultry, and eggs.Fish (specifically, fatty fish) are generally regarded as a healthy source of protein and the important fatty acids EPA and DHA, while also being a staple food within the Mediterranean Diet, which is often used as a measure of diet quality [111].However, it should also be noted that fish can be a large source of toxins/contaminants, such as mercury and microplastics, which can be damaging to health [112].Still, research has generally supported fatty fish's positive contribution to health [113], and thus, if youth are consuming less, it may be detrimental to overall wellbeing should this trend continue beyond the COVID-19 pandemic.However, the finding that meat, poultry and eggs may have slightly increased could be regarded as either positive or negative.Although it is true that red meat has been labeled as a possible carcinogen (and 2/3 studies that investigated its intake found a significant increase), eggs and poultry conversely, have commonly been considered less detrimental to health, either offering neutral or positive health benefits [114,115].As such, because of the limited number of studies which looked at these foods, and the somewhat mixed findings, it is unclear whether changes represent a positive or negative trend.
Similarly, there were mixed findings as to whether breakfast has increased or decreased during COVID-19 compared with prior.This is somewhat surprising, as evidence has suggested lack of time in the morning being a deterrent for consuming breakfast among youth [116], and by shifting to online education, it would be reasonable to assume there would be more time available during mornings, which could then lead to increased rates of breakfast consumption.However, because time is not the only deterrent to breakfast consumption, it is likely that other factors were involved as well, and there are other potential explanations such as youth not feeling pressured to eat in the mornings and having more flexibility in the time they choose to eat (compared with before the pandemic), which might explain why breakfast did not appear to increase during the COVID-19 pandemic.In addition, the finding that skipping breakfast and a general dysregulation of mealtimes among youth has been reported by a previous similar systematic review [102] further suggests that there are likely other factors involved.
When considering diet quality indices and overall assessments of diet quality, most studies found a positive change among youth, which is line with this review's previous findings that consumption of ultraprocessed foods decreased, and fruit and vegetable consumption has increased.Although the concept of a "healthy diet" is somewhat subjective and certainly prone to social desirability bias, even when diet quality indices alone are considered, 2/3 studies found a significant increase in KIDMED score, and 1/1 found a significant increase in the Adolescent Food Habits Checklist Score, compared with one study which found dietary diversity scores were reduced in 2020, and the remainder of studies finding no significant differences in diet quality scores.Although these are a small number of studies utilizing diet quality indices, it does appear that overall diet quality seems to have increased during COVID-19, compared with prior.
Finally, as only 5 studies investigated nutrient intake, there is limited evidence to confidently assess whether substantial changes have been made, and if so, among which nutrients.For instance, whereas fat was the most studied nutrient (n ¼ 4), only one study found a significant change during COVID-19, compared with prior.The remainder of the nutrients were largely not significantly different, which is somewhat surprising given that food intakes appeared to have changed.This may indicate that food changes were slight, and not large enough to alter overall nutrient intakes, or perhaps that changes in other food groups offset the overall nutrient intake changes that would have occurred.For example, in a study of both foods and nutrients, Lee et al. [68] found that in their study of 800 Korean teens, soft drink consumption was significantly increased during COVID-19 compared with prior, yet authors found no significant changes in sugar consumption (a notorious ingredient of soft drinks).In fact, the point estimate of sugar was found to decrease from 2019 to 2020, although this difference was not significant, suggesting that the increase in soft drink consumption may have been relatively small, or that other foods were changed to offset the impact on nutrient intake this might have been expected to have.It should also be noted that among the studies investigating nutrient intake, 3/5 would be considered "high quality" according to their study quality scores, and their rigor may have contributed to the null findings.Ultimately, however, more evidence is needed to definitively ascertain whether nutrient intake has significantly changed among youth during COVID-19, compared with prior, because of the limited number of studies investigating them.This review is not without limitations.First, although most studies in this review used a statistical test to compare their sample's findings to the overall population, there were a surprising number which did not, opting to present their data in the form of simple percentages and/or proportions.As such, making conclusive statements as to whether there were dietary changes within these studies is difficult, as some of these findings may be because of chance alone.However, to counteract the impact by which this might have on the findings, we have presented each increase as either a simple proportion change, or a statistically significant one, allowing for inferences to be made with this information.In addition, the findings of nonstatistically significant changes tended to mirror those of the statistically significant ones, demonstrating that although we may be less confident in those findings, they are at least not suggesting different conclusions.
Second, although we examined the quality of each study, each study was treated equally regarding analysis of food changes during the COVID-19 pandemic, and we opted to present a subanalysis of each dietary change, stratified by study quality instead (see Supplemental Table 3).This was done because studies which used a statistical test to report their findings were largely the same studies that were deemed higher quality (16/17 of "high quality" studies used a statistical test), and subgroup analysis suggested largely the same dietary changes among each group/habit.However, it should be noted that higher quality studies were much more likely to suggest null findings (particularly in the case of fruits and vegetables and ultraprocessed foods), which could potentially be attributed to their higher rigor.Still, because of the multitude of factors which determine the quality of a study within this review, and because the National Heart, Blood and Lung Institute's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies [117] does not account for all these aspects, it was decided to use a more inclusive approach and not exclude any studies from the analysis portion.Finally, because experiencing a pandemic such as the COVID-19 pandemic is a rare phenomenon (i.e., 5 occurring in the past 100 y [118]), we felt it was best to gather as much information as possible, to gain a better understanding of dietary changes among youth, and not exclude any data.
Third, most studies in this review had an HDI score of "High" or "Very High" (63/67, 94.0%), which impacted our ability to assess whether findings were contingent on the level of development of the country under study.It also somewhat limits our ability to apply our findings and conclusions to countries with lower development indices who also dealt with dietary changes during the COVID-19 pandemic.It should also be noted that our study focused solely on youth, and not the family, which one review has done previously, noting the differences in dietary changes between families with children, and those without during the COVID-19 pandemic [119].As such, both ideas represent an opportunity for future research to explore.
Lastly, this review did not attempt to quantify the magnitude of difference in food changes, which is especially important to consider when discussing food consumption changes.Unfortunately, because of the overwhelming number of ways that dietary changes were investigated, quantifying the differences across all studies would be problematic.This review found 268 unique measurements of food (see Supplemental Table 1) among the 67 studies, and even among those studying the same food, the frequency by which it was measured was often different between studies.This may be due in part to our search strategy and being somewhat unrestrictive of what could be considered a dietary change; however, we preferred this approach to consider a wider source of evidence.It is also noteworthy that most studies did not use the same questionnaires, meaning how the questions were asked also differed.As a result, although metaanalyses are useful for describing magnitudes of difference, we opted against attempting to do so.
In conclusion, results showed generally positive dietary changes among youth during COVID-19, including an increase in consumption of fruits and vegetables, decrease in intake of ultraprocessed foods, as well as a general increase in overall diet quality as measured both by diet quality indices and overall perception of changes.These are important to note as 2 previous reviews on adults have suggested negative findings regarding the impact of COVID-19 on diet quality [17,18].Furthermore, we can speculate that although COVID-19 caused parents and their children to be at home more, it appears to have had a protective effect on diet quality.As such, to continue this protective effect, it is necessary to address the school food environment so children can have access to the same healthful foods offered at home, in hopes of maintaining the positive dietary changes made by youth during COVID-19.One way to do so is via a national school lunch program, and although most developed countries possess one, ensuring the healthiness of the meals being served is just as vital.
Findings for other food groups/habits were generally mixed, or interpretation of whether they were positive or not is somewhat unclear.This review provides evidence that although the pandemic has been associated with many negative health findings, most studies suggested positive, health-promoting changes with regards to food choices among youth.Future research should investigate whether changes made during the pandemic have persisted as restrictions continue to lift, and if so, what specific aspects of the COVID-19 pandemic have caused these food changes.Future research should also strongly consider using previously validated questionnaires to improve study quality and comparability between similar studies.

1 NFIGURE 2 .
FIGURE 2. Summary of study findings.*Bolder colors indicate significant changes, whereas transparent ones represent changes of unknown statistical significance.

TABLE 1
Summary of studies

TABLE 1
(continued on next page) N. Woods et al.The Journal of Nutrition 154 (2024) 1376-1403

TABLE 2
Quality assessment (highest to lowest ranked studies)